Millipede coils

A nuclear magnetic resonance probe for analysis of a sample, comprising

• a sample holding fixture for receiving samples, and
• a Millipede coil disposed to surround said sample, said Millipede coil characterized by self inductance comprising less than 55% of the total inductance of said Millipede coil.

A method of establishing capacitive coupling between inductive elements of a millipede magnetic resonance birdcage coil having a plurality of inductive leg elements, comprising the steps of directing an auxiliary conducting member connected to one said inductive leg elements at an angle therewith and directed toward an adjacent said leg element without contact thereto, also directing an auxilliary conducting member connected to said adjacent said leg element toward said one said inductive leg element without contact therewith, establishing the relative displacement of said auxilliary conducting members to establish a desired capacitive coupling therebetween.

A millipede magnetic resonance bird cage coil for providing a substantially uniform RF field in the cylindrical interior space thereof and exhibiting a total inductance Ltotal, comprising:

• a number N of mutually isolated leg conductors disposed spaced from and surrounding an axis and principally extending parallel therewith, each said leg conductor of width w, said plurality of leg conductors defining an active volume, each said leg conductor comprising a self-inductive reactance, Lself, and pairs of said leg conductors L(j) and L(k) separated by an inter-element gap coupling to contribute an increment of mutual inductance Mj,k wherein
• (Mjj+2 / Mjj+)>0.3.

A multiply resonant magnetic resonance coil structure comprising at least two coaxially disposed birdcage coils, a first said birdcage coil comprising a Millipede coil of outside diameter D1 and exhibiting capacitive and inductive reactances for producing resonance at frequency ω1, a second birdcage coil of conventional construction having an inside diameter D2 and exhibiting capacitive and inductive reactances for producing resonance at frequency ω2, where D2>D1.

A millipede magnetic resonance bird cage coil comprising a plurality of leg elements disposed about and spaced from an axis, whereby a desired RF phase relationship is established among said leg elements, a first plurality of said elements coupled to a first end ring, a second plurality of said leg elements connected to a second end ring, a first plurality of leg elements comprising at least one leg of said first plurality comprising an auxiliary conductor directed toward a leg of said second plurality without contact therewith, a second plurality comprising at least one leg element proximate said leg element of said first plurality and said one leg element further comprises an auxiliary conducting member directed toward said one element of said first plurality without contact therewith whereby said auxiliary conductors comprise a capacitive coupling component between said respective legs.

A millipede magnetic resonance bird cage coil for providing a substantially uniform RF field in the cylindrical interior space thereof, comprising:

• a plurality of leg conductors disposed spaced from an axis and parallel therewith, said plurality of leg conductors defining an active volume, each said leg conductor comprising a substantially planar and extended member comprising a dielectric core having conductive surfaces on opposite substantially planar sides thereof, a first conductive surface disposed facing said interior space and a second conductive surface having at least an inner conductive portion removed from said substrate, said inner conductive portion distal in respect to end regions of said extended member, and end portions removed from said first conductive surface whereby said first and second surfaces are not co-extensive in said end regions;
• a pair of annular conductors disposed about said axis and coupled to adjacent said leg conductors at respective ends thereof;
• pairs of said leg conductors separated by an inter-element gaps, the mutual inductance of the birdcage coil is greater than the self inductance of the legs of said coil.